The app currently supports bitcoin wallets from Blockchain and Coinbase, and Eaze says it plans to add support for other wallets in the future.

OK Glass, make a payment

Due to the unique Google Glass user interface, Nod to Pay is somewhat different to set up than your average smartphone payments app, and sending bitcoin involves a bit more than a simple nod of the head, too.

Initially, users must link their existing wallets by scanning a QR code.

Then, to use the voice-activated app, the user needs to say “OK Glass, make a payment.” At which point, the device scans the QR code of any point-of-sale (POS) application and displays the details on the Glass display.

The next step is the nod. Nods, in fact, as the user needs to tilt the head twice to send the payment.

Due to the novel way transactions are confirmed, Eaze plans to implement an additional security level: simply, a spending limit will be set, above which PIN authentication is required.

Wearable innovation

Eaze says Nod to Pay offers a "truly handsfree" payment solution.

“We are proud to be the first to bring a global payment solution to Google Glass. After our announcement of Nod To Pay in February, we worked hard to make our product available to the public,” said Eaze co-founder Rutger van Zuidam, adding:

“With the integration of Coinbase and Blockchain.info we have also answered to the request of the market by building not yet another wallet but by making existing wallets available on Glass.”

Although the concept has been around since 2012, it was only this week that Google finally started selling Glass to the general public. At $1,500 the price seems rather steep, but it's worth bearing in mind that Glass was conceived as an elaborate tech demo rather than an actual consumer product – Google’s way of fostering innovation in the emerging wearables market.

A number of developers used the opportunity to come up with new concepts and ports of existing services to this unique form factor. A team of New York-based developers introduced the first Google Glass payment app last year, but GlassPay was designed specifically for use in bricks-and-mortar stores.

Like them or not, wearables are coming, and many developers are experimenting with a wide range of different applications, including digital wallets for smart watches and smart glasses.